Techniques for manipulating patterned features using ions

ABSTRACT

A method may include providing a surface feature on a substrate, the surface feature comprising a feature shape a feature location, and a dimension along a first direction within a substrate plane; depositing a layer comprising a layer material on the surface feature; and directing ions in an ion exposure at an angle of incidence toward the substrate, the angle of incidence forming a non-zero angle with respect to a perpendicular to the substrate plane, wherein the ion exposure comprises the ions and reactive neutral species, the ion exposure reactively etching the layer material, wherein the ions impact a first portion of the surface feature and do not impact a second portion of the surface feature, and wherein an altered surface feature is generated, the altered surface feature differing from the surface feature in at least one of: the dimension along the first direction, the feature shape, or the feature location.

RELATED APPLICATIONS

This application is a Continuation of, and claims the benefit ofpriority to, U.S. patent application Ser. No. 15/142,526, filed Apr. 29,2016, entitled “TECHNIQUES FOR MANIPULATING PATTERNED FEATURES USINGIONS,” and claims the benefit of U.S. Provisional Application No.62/305,308 filed Mar. 8, 2016, entitled “TECHNIQUES FOR MANIPULATINGPATTERNED FEATURES USING IONS.” U.S. patent application Ser. No.15/142,526 and U.S. Provisional Application No. 62/305,308 areincorporated by reference herein in their entirety.

FIELD

The present embodiments relate to transistor processing techniques, andmore particularly, to processing for three dimensional device formation.

BACKGROUND

As semiconductor devices continue to scale to smaller dimensions, theability to pattern features becomes increasingly difficult. Thesedifficulties include in one aspect the ability to obtain features at atarget size for a given technology generation. Another difficulty is theability to obtain the correct shape of a patterned feature, as well asthe correct placement of a patterned feature.

With respect to these and other considerations the present improvementsmay be useful.

BRIEF SUMMARY

In one embodiment, a method may include providing a surface feature on asubstrate, the surface feature comprising a feature shape a featurelocation, and a dimension along a first direction within a substrateplane; depositing a layer comprising a layer material on the surfacefeature; and directing ions in an ion exposure at an angle of incidencetoward the substrate, the angle of incidence forming a non-zero anglewith respect to a perpendicular to the substrate plane, wherein the ionexposure comprises the ions and reactive neutral species, the ionexposure reactively etching the layer material, wherein the ions impacta first portion of the surface feature and do not impact a secondportion of the surface feature, and wherein an altered surface featureis generated, the altered surface feature differing from the surfacefeature in at least one of: the dimension along the first direction, thefeature shape, or the feature location.

In another embodiment, a method of processing a substrate may includeproviding a cavity in the substrate, the cavity having a first dimensionalong a first direction within a substrate plane and a second dimensionalong a second direction within the substrate plane, the seconddirection being perpendicular to the first direction; depositing a layercomprising a layer material within the cavity; and directing ions in anion exposure at an angle of incidence toward the substrate, the angle ofincidence forming a non-zero angle with respect to a perpendicular tothe substrate plane; wherein the ion exposure comprises the ions andreactive neutral species, the ion exposure reactively etching the layermaterial, wherein the ions impact a first portion of the cavity and donot impact a second portion of the cavity, and wherein the firstdimension is selectively altered with respect to the second dimension.

In a further embodiment, a method of processing a substrate may includeproviding a cavity in the substrate, the cavity disposed at a firstcavity location within the substrate; depositing a layer comprising alayer material within the cavity; and directing ions in an ion exposureat an angle of incidence toward the substrate, the angle of incidenceforming a non-zero angle with respect to a perpendicular to thesubstrate plane; wherein the ion exposure comprises the ions andreactive neutral species, the ion exposure reactively etching the layermaterial, wherein the ions impact a first portion of the cavity and donot impact a second portion of the cavity, and wherein the cavity isdisposed at a second cavity location in the substrate after the ionexposure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D depict one example of processing of a device structureaccording to various embodiments of the disclosure;

FIGS. 2A-2D depict another example of processing of a device structureaccording to embodiments of the disclosure;

FIGS. 3A-3G depict processing of a device structure according to furtherembodiments of the disclosure;

FIGS. 4A-4B depict processing of a device structure according to otherembodiments of the disclosure;

FIGS. 5A-5C show processing of a device structure according toadditional embodiments of the disclosure;

FIGS. 6A-6F illustrate processing of a device structure according tostill other embodiments of the disclosure;

FIG. 7A to FIG. 7C illustrate another example of processing a deviceaccording to some embodiments of the disclosure;

FIGS. 8A-8G another example of processing a device according to someadditional embodiments of the disclosure;

FIG. 9A illustrates an exemplary processing apparatus according toembodiments of the disclosure; and

FIG. 9B depicts details of an exemplary extraction plate according toembodiments of the disclosure.

DETAILED DESCRIPTION

The present embodiments will now be described more fully hereinafterwith reference to the accompanying drawings, where some embodiments areshown. The subject matter of the present disclosure may be embodied inmany different forms and are not to be construed as limited to theembodiments set forth herein. These embodiments are provided so thisdisclosure will be thorough and complete, and will fully convey thescope of the subject matter to those skilled in the art. In thedrawings, like numbers refer to like elements throughout.

This present embodiments provide novel techniques to pattern substratesand in particular novel techniques to modify a feature disposed on asubstrate surface or extending from a substrate surface into thesubstrate. As used herein the term “substrate” may refer to an entitysuch as a semiconductor wafer, insulating wafer, ceramic, as well as anylayers or structures disposed thereon. As such, a surface feature,layer, series of layers, or other entity may be deemed to be disposed ona substrate, where the substrate may represent a combination ofstructures, such as a silicon wafer, oxide layer, and so forth.

In various embodiments, the surface feature may be used for patterning alayer disposed underneath the surface feature. Examples of a surfacefeature include a hole formed within a layer, such as a via, or trench.In other examples a surface feature may be a pillar, a mesa structure, aline structure (line), or other feature extending above a substrate. Theterm “hole” may refer to a structure extending through the entirety of alayer, such as a via. The term “hole” may also refer to a structure suchas a depression or recess formed within a layer not extending throughthe entirety of the thickness of a layer. Moreover, the term “layer” asused herein may refer to a continuous layer, a semicontinuous layerhaving blanket regions and regions of isolated features, or a group ofisolated features generally composed of the same material and disposedon a common layer or substrate.

In various embodiments, techniques are provided to modify a surfacefeature or surface features. The techniques may be applied to thesurface features after lithography processing is performed to form thesurface feature(s). In various embodiments, the surface feature may bedefined in photoresist, a hard mask material such as oxide, nitride, orcarbon containing material, or other material. This post-lithographyprocessing may overcome shortfalls of known lithography, especially atthe nanometer scale, such as for features having minimum dimensions inthe range of 2 nm to 100 nm. The embodiments are not limited in thiscontext.

Various embodiments are related to lithographic patterning andsubsequent etching of patterned features used to fabricate features in asubstrate, such as a device feature or group of features including anintegrated circuit. The techniques disclosed herein in particularaddress problems associated with fabricating smaller patterned featureswhere the patterned features may be more closely packed than inarrangements achievable through optical lithography alone. Variousembodiments also address problems associated with pattern positioningand registration.

The present embodiments provide improvements over known techniques suchas directional deposition, photoresist trim, focused ion beammodification, shrink etch, and tapered etch during etch of mask. In thelatter technique, a feature may shrink in all directions. Notably, if afeature is asymmetric, the shrink is greater in the longer dimension.

In accordance with various embodiments a multiple operation processincludes a deposition operation, such as a conformal depositionoperation, where the deposition operation is performed onlithographically defined features, referred to herein as a “surfacefeature.” This deposition operation may be performed on a developedphotoresist feature. or alternatively on a feature formed in an etchedfilm making up part or all of a hardmask, where the hardmask willeventually define the feature in the target material. Alternatively, thesurface feature may comprise a final material in a substrate, where thefinal material is not subsequently removed.

In a subsequent operation, a directed etch including an ion exposure maybe performed to etch at least a portion of the surface feature in amanner achieving one of the following: (a) a feature reduced indimension along a first direction while not reduced in dimension along asecond direction orthogonal to the first direction; (b) a new featurewhere the new feature is reduced in dimension in a first direction andis longer in dimension than the original surface feature in the seconddirection orthogonal to the first direction; (c) a feature shifted inposition relative to its original position. As used herein the term“dimension” may refer to a length, width, depth or height of a featuresuch as a surface feature along a given direction. In variousembodiments, the surface feature may be reduced in size in addition tobeing shifted from an original position. According to some embodiments,the material deposited in the deposition operation may be a firstmaterial different to the second material used as the mask material,i.e., the patterned feature material before processing.

One advantage to these embodiments is realized where an etch havingselectivity to just the deposited material can be taken advantage of,while the original mask material of the surface feature serves as anetch stop. This selectivity can help improve within-wafer uniformity andlocal critical dimension uniformity (LCDU) of the patterned features. Inother embodiments, the material deposited in the deposition operationmay be the same as the mask material (substrate feature material beforeprocessing). This latter approach avoids complications during the finaletch transfer to the target layer when the mask is composed of more thanone material.

In still additional embodiments, the deposition process may becontrollably varied across a wafer (substrate) using techniquesavailable in a deposition chamber used to perform the selectivedeposition. This variation may achieve controllably variable changes tothe dimensions of targeted features. For example, multi-zone heatingacross different portions of a substrate may achieve this result. In asubsequent operation, if a uniform etch is performed, local overlayerror or variation in critical dimension (CD) may be reduced oreliminated by the intervening selective deposition operation.

FIGS. 1A-1D depict one example of processing a substrate such as adevice structure according to various embodiments of the disclosure. InFIG. 1A there is shown a side cross-sectional view of a substrate 100including a surface feature in the form of a cavity 102. In variousembodiments, the cavity 102 may be a lithographically patterned featureformed by a known technique. The substrate 100 includes a substrate base104, where the substrate base 104 may be composed of a first material.As noted in some examples, the substrate base 104 may be a hard maskmaterial, a material such as SiO₂, or anti-reflective coating (ARC).Examples of known ARC materials may include silicon, carbon, or othercombination of materials. The embodiments are not limited in thiscontext. The substrate 100 may be patterned by known lithographictechniques to form the cavity 102. As shown in FIG. 1C, presenting aplan view, the cavity 102 may have a rectangular shape such asappropriate for a contact or via. The illustration in FIG. 1C is forpurposes of clarification, and the cavity may assume any shape includingcurved shapes, or complex shapes in other embodiments. In accordancewith various embodiments, a layer 106 may be deposited on the substratebase 104, where the layer 106 is also deposited within the cavity 102and coats the cavity 102. In some embodiments the layer 106 may bedeposited in a conformal manner so vertical surfaces (parallel to theZ-axis) as well as horizontal surfaces (parallel to the X-Y plane) arecoated. In various embodiments, the layer thickness of layer 106 may bechosen so the layer thickness is less than approximately half of thesmallest dimension (along the X-axis). The embodiments are not limitedin this context. The layer 106 may be deposited by chemical vapordeposition (CVD), physical vapor deposition (PVD), atomic layerdeposition (ALD), or other technique. The embodiments are not limited inthis context. The layer 106 may comprise a second material differentfrom the first material of the substrate base 104, or the layer 106 maycomprise a same material as the first material of the substrate 104. Forexample, the layer 106 may be SiN, SiO₂, SiARC, TiN. To name just oneexample where the material of layer 106 differs from the substrate base104, the layer may be SiN while the base is SiO₂. Such a combination,among others, allows the substrate base 104 to act as an etch stop foretching of layer 106 given the appropriate etch chemistry where SiN isetched selectively with respect to SiO₂. As an example, the cavity 102may have dimensions of 10 nm, 20 nm, or 50 nm, while the thickness ofthe layer 106 is less than 5 nm, 10 nm, or 25 nm, respectively.

According to various embodiments, in a subsequent operation, directionalions, shown as ions 110, may be directed to the substrate 100 in an ionexposure as shown in FIG. 1A. The ions 110 may be directed at an angleof incidence forming a non-zero angle (θ) with respect to aperpendicular 120 to the substrate plane P. According to variousembodiments, the angle θ, may vary between 5 degrees and 85 degrees. Theembodiments are not limited in this context.

The ions 110 may accordingly strike at least one sidewall, in this caseshown as sidewall 108. In various embodiments, the ions 110 may beprovided in an ion exposure including a reactive mixture, where thereactive mixture etches the layer material of layer 106. The reactivemixture may be effective to volatilize layer material of layer 106 somaterial is evacuated and does not redeposit on other portions of thesubstrate 100 or cavity 102, as in known reactive ion processes. Etchingof the layer material of layer 106 may in particular occur in regions ofthe substrate 100 impacted by the ions 110 Various embodiments extend tothe use of a broad array of gas mixtures used for conventional reactiveion etching (RIE) processing. Thus, in addition to providing ions to asubstrate at a chosen angle(s) of incidence, the substrate 100 issimultaneously exposed to reactive species, where the reactive species,together with the incident ions, generate reactive etching of at leastthe layer 106 of the substrate. One chemical system commonly used in theindustry for RIE processing is CH₃F mixed with O₂. This chemical systemrepresents a known system for selectively etching SiN with respect toSift or Si. Another example is the use of CF₄ or C₄F₈ for etching SiO₂.A further example is the use of Cl₂ based chemistry for etching TiN. Inother embodiments, any known RIE etch recipes may be applied for etchingthe layer 106 according to the composition of layer 106 and thecomposition of substrate base 104. The use of this chemical system inRIE processing leads to two competing mechanisms taking place on thesurfaces of all materials on a substrate subjected to the RIE plasma.The first mechanism is etching of the surfaces of the substrate, whilethe second mechanism is deposition of a carbon-based polymer onsubstrate surfaces. Under certain process conditions polymer depositionmay be useful as the dominant mechanism at the substrate surface whennot subject to ion bombardment. Notably, energetic ion bombardment byspecies extracted from the RIE plasma can break apart the polymer andproduce dangling bonds at the material surface, causing etching of thesurface to become the dominant mechanism. Many other chemical systemsmay be used as needed to provide a reactive ion etching processaccording to the material to be reactively etched, as will beappreciated by those of skill in the art.

In the operation generally depicted in FIG. 1A, the substrate 100 may beexposed to reactive neutral species 124, where the reactive neutralspecies are derived from precursor gas composition used to generate theRIE plasma. The reactive neutral species 124 may arrive isotropically tothe substrate 100, where every portion of the different exposed surfacesof the substrate 100 are impacted by the reactive neutral species 124,as shown in FIG. 1A. Notably, the present embodiments harness theprinciples of known RIE processing where etching of a given surface isenhanced in the presence of ions. Notably, in accordance with thepresent embodiments, etching may take place just in regions of thesubstrate 100 impacted by the directional ions, i.e., in regionsimpacted by the ions 110, while leaving other surfaces unetched.

Turning now to FIG. 9A an exemplary processing apparatus, shown asprocessing apparatus 900, is illustrated, for providing an ion exposureas also illustrated in FIG. 1A. The processing apparatus 900 may be aknown compact plasma processing system generating an ion beam shown asthe ions 110. The ion beam may be extracted from a plasma 904 generatedin a plasma chamber 902 by any known technique. The processing apparatus900 may include an extraction plate 906 having an extraction aperture908, where the ions 110 are extracted as an ion beam from the plasma 904and directed to the substrate 100. As shown in FIG. 9B, the extractionaperture may be elongated along the Y-axis, providing a ribbon ion beamextending, for example, over an entire substrate along the directionparallel to the Y-axis. In various embodiments, the substrate 100 may bedisposed on a substrate holder 910 and scanned along the X-axis toprovide coverage at different regions of the substrate 100 or over theentirety of the substrate. In other embodiments, the extraction aperture908 may have a different shape such as a square or circular shape.

In some embodiments, the plasma chamber 902 may also serve as adeposition process chamber to provide material for depositing on thesubstrate 100 in the deposition operation preceding etching. Thesubstrate holder 910 may further include a heater assembly 911 forselectively heating the substrate 100 to different temperatures indifferent regions within the X-Y plane for selectively changing theamount of depositing material as discussed above.

During an ion exposure, reactive species may be provided or created inthe plasma chamber 902 and may also impinge upon the substrate 100.While various non-ionized reactive species may impinge upon all surfacesof substrate 100 including different surfaces in cavity 102, etching maytake place in areas impacted by the ions 110, as in known RIE processes,while little or no etching takes place in regions not impacted by ions110. Thus, referring to FIG. 1C discussed below, a first portion 112 ofa given surface feature such as cavity 102 impacted by the ions 110 maybe etched at a first rate, while a second portion 114 of cavity 102 notimpacted by ions is etched at a second rate less than the first rate. Insome examples, the second rate may be zero or may be much less than thefirst rate.

As a result, as shown in FIGS. 1B and 1D, selective etching of thedeposited layer, layer 106, may take place along the right sidewall asshown in FIG. 1B, shown as sidewall 108. The result of the depositionprocess for depositing layer 106 and selective directional etching of aportion of layer 106 in cavity 102, is the reduction in width of cavity102 from width W1 to width W2 along the x-axis, as well as a reductionin length along the X-axis. As further shown in FIG. 1C, the ions 110may be directed along a first direction with respect to the X-Y plane,such as along the X-axis. In this manner the first portion 112 may bethe region of the cavity 102 lying along the right sidewall parallel tothe Y-axis, since this region faces the ions 110 and is perpendicular tothe direction of ions 110, and accordingly is disposed to intercept theions 110. The second portion 114 may be the region of the cavity 102lying along sidewalls parallel to the X-axis since these regions mayreceive little or no impact as ions travel parallel to the surface ofthese regions. The second portion 114 may also extend to the regions ofthe cavity 102 along left sidewall as shown in FIG. 1C, since thisregion is shadowed from the ions 110. Because just the layer 106 alongthe right sidewall is removed due to direction of ions 110 (see alsoFIG. 1C for the orientation of ions 110 within the X-Y plane), thereduction in width of cavity 102 from W1 to W2 along the directionparallel to X-axis may correspond to the thickness of layer 106 in thisexample, while the reduction in length of cavity 102 along the directionparallel to the Y-axis from L1 to L2 corresponds to twice the thicknessof layer 106.

In various embodiments, the ions 110 may be directed in an exposurewhere reactive etching of layer 106 is selective with respect to etchingof substrate base 104, where the substrate base 104 is a differentmaterial than material of layer 106. For example, layer 106 may be aphotoresist while substrate base 104 is an oxide material. Accordingly,etching may cease of decrease drastically once layer 106 is removed fromsidewall 108.

Accordingly, the multiple operation process outlined in FIGS. 1A-1Daffords the ability to selectively change the dimensions of the cavity102, for example, where a first dimension is selectively altered withrespect to a second dimension, e.g., where the dimension along theY-axis is changed to a different extent as compared to the dimensionalong the X-axis.

FIGS. 2A-2D depict another example of processing of a substrateaccording to embodiments of the disclosure. In the example shown, theconventions of FIGS. 1A-1D may apply while like reference numbers referto similar or the same entities. In FIGS. 2A-2D there is shown aconformal deposition process, where the conformal deposition process mayform an initial operation to be followed a directional etch process,such as depicted in FIGS. 3A-3G discussed below. In FIGS. 2A and 2B asubstrate 200 is provided having a cavity 202, in this case of circularshape, within a base 204. In FIGS. 2C and 2D a layer 206 is deposited asgenerally described above with respect to layer 106. The deposition ofthe layer 206 may have the effect of reducing the diameter of cavity 202by from W1 to W2 by an amount equal to twice the thickness of layer 206as shown.

FIGS. 3A-3G depict processing of a device structure according to furtherembodiments of the disclosure. For clarity, in the figures to follow,the reactive neutral species 124 are not shown. In FIG. 3A and FIG. 3Bthere is shown the substrate 200 after deposition of the layer 206.Turning now to FIG. 3C and FIG. 3D there is shown an example ofselective etching of the layer 106, where the ions 210 form trajectoriesparallel to the Y-axis and are directed to surfaces of the cavity 202generally oriented along the X-axis, including opposite sidewallportions, while not necessarily parallel to the Y-axis. In this example,the ions 210 travel parallel to the Y-axis and accordingly do not impactthe layer 206 in regions generally oriented along the Y-axis, whileimpacting regions of layer 206 more oriented parallel to the X-axis.Accordingly, the resulting structure has no material of layer 206 alongthe vertical cut (parallel to the Y-axis) shown in FIG. 3C, while thelayer 206 is preserved at least in part in portions of the sidewalls ofcavity 202 lying along the horizontal cut. In different embodiments,depending upon the angle of incidence θ of ions 210, the width of cavity202 and height of cavity 202 (along the Z-axis), the ions 210 may or maynot impact the bottom of cavity 202. In the example of FIG. 3D and FIG.3F the ions 210 do not impact the bottom of cavity 202, leaving layer206 intact, while in the example of FIG. 3E and FIG. 3G, ions 210 doimpact the bottom surface of cavity, removing the layer 206. As a resultof the operations of FIGS. 2-3 the shape and size of cavity 202 ischanged from a circular shape to an elongated shape, such as an ovalshape or elliptical shape as shown in FIG. 3C.

In the FIGS. 4A to 8C to follow directional ion etching processes aredepicted in plan view. Notably in these depictions, the trajectories ofions form a non-zero angle with respect to the perpendicular 120 asillustrate in FIG. 1A. In the example of FIG. 4A and FIG. 4B theoperations depicted in FIG. 2 and FIG. 3 may be extended wherein etchingusing directional ions along the directions shown in FIGS. 3D and 3F iscontinued after layer 206 is removed. In these embodiments, the etchingspecies used to etch layer 206, such as ions 210 in combination withother reactive species, may also be effective to etch the base 204,where the base 204 may be made of a base material, where the basematerial is the same material or a different material from layer 206. Asshown in FIG. 4B, a more elongated oval shape is formed having greater adimension than the original dimension of cavity 202 along the Y-axis andshorter dimension along the X-axis as opposed to the original dimension.In some examples the greater dimension of an elongated shape may betwice the shorter dimension, or five times the shorter dimension. Theembodiments are not limited in this context.

FIGS. 5A-5C show processing of a device structure according toadditional embodiments of the disclosure. In this example a substrate500 having a base 504 is provided with a trench 502 elongated along theX-axis and having a racetrack shape. In FIG. 5A, the structure is shownafter a deposition process is performed to deposit a layer 506 withinthe trench 502. The length of the trench 502 has been reduced along theX-axis from an original length L1 by an amount equal to 2 times thethickness of the layer 506 as shown by L2. The width along the Y axis oftrench 502 has been reduced by a similar amount from an original widthW1 to W2. As shown in FIG. 5B, the trench 502 may be etched by directingions 503 toward endwalls 508 and at a non-zero angle of incidence θ withrespect to a perpendicular to a substrate plane of base 504 (see FIG. 1Afor further definition of θ). As a result, layer 506 may be removedalong the endwalls 508. As a result of the deposition of layer 506 andthe direction reactive etching of trench 502 the trench width may beselectively reduced along the Y-axis to W2 while restoring the length ofthe trench 502 along the X-axis to the original length L1, since thelayer 506 remains just along the portions of the trench 502 lyingparallel to the ions 503. To facilitate restoration of the length of thetrench 502 to its original length L1 before deposition of layer 506,etch chemistry is used providing a high degree of selectivity of etchingmaterial of layer 506 with respect to the material of base 504. In thismanner the etching may cease when the base material of base 504 isencountered.

In the example of FIG. 5C, the structure of FIG. 5A may be etched usingions 505, where the ions 505 are directed in a similar manner as theprocess of FIG. 5B to the endwalls 508. In this example, the etchingprocess using ions 505 may be continued to etch material within base 504so the length L3 of the trench 502 is greater than its original lengthL1 before deposition of layer 506. In some variants, the etchcomposition of species used during ion etching of base 504 may bechanged from the etch composition used to etch the layer 506.Alternatively, the etch composition chosen to etch layer 506 and base504 may be the same composition and may be relatively non-selectivewhere the etch rate of layer 506 is similar to the etch rate of base504.

FIGS. 6A-6F illustrate processing of a substrate according to stillother embodiments of the disclosure. In this example, in FIG. 6A thetrench 502 is again shown after formation of the layer 506, reducing theoriginal trench size including the length along the X-axis from L1 toL2. In FIG. 6B, ions 603 are directed along trajectories parallel to theX-axis just to the right endwall, shown also as endwall 508, resultingin the trench 502 having reduced dimensions along three sides, whileretaining the original position of the right endwall before depositionof layer 506. In FIG. 6C ions 605 are directed toward the right sidewallto continue etching of the trench 502, as generally described above withrespect to FIG. 5C, except in this case the ions 605 are just directedto the right as shown. This etching process allows for formation of atrench 502 having a narrower width W2 along the Y-axis, and shiftedposition (location) with respect to the original trench location shownin FIG. 6A. Depending upon the extent of etching performed in theoperation of FIG. 6C, the length of the trench along the X-axis may begreater than L1 of the original trench, or may be the same as L1, asdepicted in FIG. 6C. Accordingly, FIG. 6C provides a specific examplewhere a surface feature location, in this case a trench location withrespect to a position along the X-axis, is shifted, while the trench isalso selectively narrowed along the Y-axis.

Turning to FIG. 6D there is shown a substrate 610 having a cavity ofcircular shape after deposition of a layer 616. In FIG. 6E a resultingshape of the cavity 612 is shown when ions 614 are directed just towardthe upper (in FIG. 6E) sidewall 615, resulting in a cavity 612 where theposition of the upper sidewall region is the same as before depositionas layer 616, while other regions of cavity 612 are reduced in size,resulting in a more oval shape. As shown in FIG. 6F, further etching byions 618 may be performed along the same direction as ions 614, wherethe ions 618 may be similar to or different from the ions 614. Thisfurther etching results in etching into base 604 along the samedirection as in FIG. 6E, and may result in a more elongated oval shape.

Turning now to FIG. 7A and FIG. 7B there is shown a further example ofprocessing a cavity, where the trench 502 is formed as described aboveby depositing a layer 506. Subsequently, ions such as the ions 603, or acombination of ions 603 and ions 605, may be directed along the X-axisto etch just the right endwall, shown as endwall 508 in FIG. 7B. Byproper selection of etching conditions and etching time, the resultingtrench, shown as trench 502, may have the same length, shown as L1, asbefore deposition of layer 506, while the center of the trench 502 alongthe X-axis in FIG. 7B is shifted to the right with respect to trench 502of FIG. 7A. Furthermore, in a second directional etching operation shownin FIG. 7C, ions 702 may be directed parallel to the Y-axis to the topedge 704 and bottom edge 706 of the trench 502. In some embodiments, thematerial of layer 506 may differ from the material of base 504 whereinetching by the ions 702 of the layer 506 is highly selective withrespect to the etching of base 504. For example, ions 702 may beprovided in a reactive ion etch process for etching layer 506 at a ratetwice as fast as the etching of base 504, or five times as fast, 10times as fast, or 20 times as fast. The embodiments are not limited inthis context. In this manner, the layer 506 may be completely removedfrom the bottom edge 706 and top edge 704, while little or no materialfrom base 504 is removed from these edges. This etching allows theoriginal trench width W1 to be restored, corresponding to the trenchwidth before deposition of layer 506. A net result of these processes isshown in FIG. 7C, where the trench 502 is shifted to the right from anoriginal trench location before deposition of layer 506, as shown by thedashed curve in FIG. 7A, while the original dimensions of the trench 502are preserved. In various embodiments, the cavity location for anycavity shape may be shifted from a first cavity location to a secondcavity location in a like manner to the operations of FIGS. 7A-7C whilepreserving the original cavity dimensions.

FIGS. 8A-8G another example of processing a substrate according to someadditional embodiments of the disclosure. In the example of FIG. 8A andFIG. 8D, a substrate 800 is provided with a pillar 802 extending above abase 804. The pillar 802 may, but need not be, a different material thanthe material of base 804. In FIG. 8B and FIG. 8E a layer 806 isdeposited, as generally described above. In FIG. 8C ions 812 aredirected toward the pillar 802 in two opposite directions, where theopposite directions lie parallel to the Y-axis as shown, resulting inremoval of layer 806 from regions generally more aligned along theX-axis, as further shown in the cut sections of FIG. 8F and FIG. 8G.Accordingly, the original diameter D1 is increased to a diameter D2along the X-axis, as shown in FIG. 8D, while the original diameter D1may be maintained along the X-axis, as shown in FIG. 8B. Thisdirectional etching allows the originally circular shape of the pillar802 to be transformed to an oval shape as illustrate in FIG. 8C.

In further embodiments, directional etching of ions may be performed byrotating a substrate within the X-Y plane to any desired angle. Thus, atrench feature may be oriented with its long axis at a 45 degree anglewith respect to the Y-axis while a ribbon beam directed to the trenchfeature has its axis oriented along the Y-axis as in FIG. 9B.

In additional embodiments, an operation involving deposition of a layeron a surface feature followed by selective directional etching of thesurface feature as described above, may be repeated in an iterativefashion. A given cycle may be composed of deposition of a layer followedby etching of the surface feature including the deposited layer along agiven direction. This given cycle may be repeated a desired number oftimes to adjust the dimension of a feature selectively along a givendirection, to adjust the shape, or adjust the position, for example.

In additional embodiments, by scanning a substrate with respect to anion beam such as along the X-axis as generally shown in FIG. 9B, thepossibility is afforded to vary a directed etch across the substrate toachieve location-specific directional selectivity of etching, sofeatures within a certain region, such as region 912 of the substratemay be altered to one extent while features in another region, such asregion 914, are not altered or are altered to a different extent or in adifferent fashion. For example, an ion beam, shown as ions 110 may bepresent when region 912 is under extraction aperture 908, while the ionbeam is extinguished when the region 914 is under extraction aperture908.

The present embodiments provide various advantages over conventionalprocessing to define features in a substrate. Currently, there are noknown techniques able to achieve what is described in these embodiments,in particular over a full wafer in a manufacturing environment. Severalproblems may be solved with these embodiments including a firstadvantage of being able to shift a surface feature within a substrate ina desired direction and in a desired amount. The present embodimentsalso proved the advantage where a feature may be shifted and theoriginal feature shape or dimensions may be preserved or changed.Another advantage of the present embodiments is the ability to generateotherwise unobtainable feature dimensions and shapes. Further advantagesinclude the ability to provide for overlay correction, providing foroverlay margin improvement, providing tip-to-tip separation reductionbetween adjacent features to dimensions not otherwise obtainable,contact resistance reduction in structures formed according to thepresent embodiments, increase in pattern density, and elimination of acut-mask operation.

The present disclosure is not to be limited in scope by the specificembodiments described herein. Indeed, other various embodiments of andmodifications to the present disclosure, in addition to those describedherein, will be apparent to those of ordinary skill in the art from theforegoing description and accompanying drawings. Thus, such otherembodiments and modifications are in the tended to fall within the scopeof the present disclosure. Furthermore, the present disclosure has beendescribed herein in the context of a particular implementation in aparticular environment for a particular purpose, while those of ordinaryskill in the art will recognize the usefulness is not limited theretoand the present disclosure may be beneficially implemented in any numberof environments for any number of purposes. Thus, the claims set forthbelow are to be construed in view of the full breadth and spirit of thepresent disclosure as described herein.

What is claimed is:
 1. A method, comprising: providing a cavity on asubstrate; depositing a layer comprising a layer material on the cavity;and directing ions in an ion exposure along a first direction, and at anangle of incidence toward the substrate, the angle of incidence forminga non-zero angle with respect to a perpendicular to the substrate plane,wherein the ion exposure reactively etches the layer material, whereinthe ions impact a first sidewall of the cavity, along an entirety of thefirst sidewall, the first sidewall extending perpendicularly to thefirst direction, and wherein the ions do not impact a second sidewall ofthe cavity, the second sidewall of the cavity extending along the firstdirection.
 2. The method of claim 1, wherein the cavity comprises afirst dimension along the first direction and a second dimension along asecond direction perpendicular to the first direction, and wherein thedepositing the layer comprises performing a shrink of the cavity whereinthe first dimension and second dimension are reduced.
 3. The method ofclaim 1, wherein the cavity comprises a circular shape before the ionexposure and comprises an elongated shape after the ion exposure.
 4. Themethod of claim 1, wherein the layer material is removed from a bottomsurface of the cavity after the etching.
 5. The method of claim 2,wherein the cavity is formed within a substrate material before the ionexposure, and wherein the ion exposure comprises etching the substratematerial along the first direction to form an elongated shape, whereinthe elongated shape comprises a third dimension along the firstdirection, the third dimension being greater than the first dimension.6. The method of claim 2, wherein the cavity comprises a trench beforethe depositing the layer, wherein the first dimension is greater thanthe second dimension, and wherein after the depositing the layer andafter the ion exposure, the trench comprises a third dimension along thesecond direction, the third dimension being less than the firstdimension, and further comprises the first dimension along the firstdirection.
 7. The method of claim 2, wherein the cavity comprises atrench before the depositing the layer, wherein the first dimension isgreater than the second dimension, and wherein after the depositing thelayer and after the ion exposure, the trench comprises a third dimensionalong the second direction, the third dimension being less than thefirst dimension, and further comprises a fourth dimension along thefirst direction, the fourth dimension being greater than the firstdimension.
 8. The method of claim 1, wherein a location of the cavity isshifted from a first location within the substrate before the depositingthe layer to a second location within the substrate after the ionexposure.
 9. The method of claim 8, wherein after the depositing thelayer and the ion exposure a dimension of the cavity is reduced alongthe second direction, and wherein the first dimension along the firstdirection is not altered.
 10. The method of claim 8, wherein after thedepositing the layer and the ion exposure a dimension of the cavity isreduced along the second direction, and wherein the first dimensionalong the first direction is increased.
 11. The method of claim 1,wherein the ions are directed as a ribbon ion beam, the ribbon beamhaving an axis parallel to the second direction.
 12. The method of claim1, wherein the cavity is formed within a substrate material before thedepositing the layer, and wherein the substrate material acts as an etchstop for the ion exposure.
 13. A method of processing a substrate,comprising: providing a cavity in the substrate, the cavity having afirst dimension along a first direction within a substrate plane and asecond dimension along a second direction within the substrate plane,the second direction being perpendicular to the first direction;depositing a layer comprising a layer material within the cavity; anddirecting ions in an ion exposure along the first direction, and at anangle of incidence toward the substrate, the angle of incidence forminga non-zero angle with respect to a perpendicular to the substrate plane,wherein the ion exposure reactively etches the layer material, whereinthe ions impact a first sidewall of the cavity, along an entirety of thefirst sidewall, the first sidewall extending along the second direction,wherein the ions do not impact a second sidewall of the cavity, thesecond sidewall of the cavity extending along the first direction, andwherein the first dimension is selectively altered with respect to thesecond dimension.
 14. The method of claim 12, wherein the firstdimension is reduced while the second dimension is not reduced.
 15. Themethod of claim 13, wherein the second dimension is increased.
 16. Amethod of processing a substrate, comprising: providing a cavity in thesubstrate, the cavity disposed at a first cavity location within thesubstrate; depositing a layer comprising a layer material within thecavity; and directing ions in an ion exposure along a first directionand at an angle of incidence toward the substrate, the angle ofincidence forming a non-zero angle with respect to a perpendicular tothe substrate plane, the ion exposure reactively etching the layermaterial, wherein the ions impact a first sidewall of the cavity, alongan entirety of the first sidewall, the first sidewall extendingperpendicularly to the first direction, wherein the ions do not impact asecond sidewall of the cavity, the second sidewall of the cavityextending along the first direction, and wherein the cavity is disposedat a second cavity location in the substrate after the ion exposure. 17.The method of claim 16, wherein the cavity comprises a trench, andwherein a trench location is shifted along the first direction, andwherein the trench is selectively narrowed along the second direction.